The association between dyslipidaemia in the first trimester and adverse pregnancy outcomes in pregnant women with subclinical hypothyroidism: a cohort study.

BACKGROUND: Subclinical hypothyroidism (SCH) is linked to dyslipidaemia and adverse pregnancy outcomes. However, the impact of dyslipidaemia on the outcome of pregnancy in SCH is unclear. METHODS: We enrolled 36,256 pregnant women and evaluated their pregnancy outcomes. The following data was gathered during the first trimester (≤ 13+ 6 weeks of gestation): total cholesterol (TC), low-density lipoprotein (LDL-C), triglyceride (TG), high-density lipoprotein (HDL-C), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) concentrations. The reference ranges for lipids were estimated to range from the 5th to the 95th percentile. Logistic regression assessed the relationships between dyslipidaemia and adverse pregnancy outcomes, including abortion, preeclampsia/eclampsia, low birth weight, foetal growth restriction, premature rupture of foetal membranes, gestational hypertension, preterm birth, macrosomia and gestational diabetes mellitus (GDM). Additionally, the best thresholds for predicting adverse pregnancy outcomes based on TSH, FT4, and lipid levels were determined using receiver operating characteristic curves. RESULTS: In the first trimester, LDL-C > 3.24 mmol/L, TG > 1.92 mmol/L, HDL-C < 1.06 mmol/L, and TC > 5.39 mmol/L were used to define dyslipidaemia. In this cohort, 952 (3.56%) patients were diagnosed with SCH, and those who had dyslipidaemia in the first trimester had higher incidences of gestational hypertension (6.59% vs. 3.25%), preeclampsia/eclampsia (7.14% vs. 3.12%), GDM (22.53% vs. 13.77%), and low birth weight (4.95% vs. 2.08%) than did those without dyslipidaemia. However, after adjusting for prepregnancy body mass index (pre-BMI), dyslipidaemia was no longer related to these risks. Furthermore, elevated TG dyslipidaemia in SCH patients was connected to an enhanced potential of gestational hypertension (odds ratio [OR]: 2.687, 95% confidence interval [CI]: 1.074 ~ 6.722), and elevated LDL-C dyslipidaemia correlated with increased preeclampsia/eclampsia risk (OR: 3.172, 95% CI: 1.204 ~ 8.355) after accounting for age, smoking status, alcohol use, pre-BMI, and levothyroxine use. Additionally, the combination of TC, TG, LDL-C, pre-BMI, and TSH exhibited enhanced predictive capabilities for gestational hypertension, preeclampsia/eclampsia, and GDM. Values of 0.767, 0.704, and 0.706 were obtained from the area under the curve. CONCLUSIONS: Among pregnant women with SCH, dyslipidaemia in early pregnancy was related to elevated risks of adverse pregnancy consequences. The combined consideration of age, pre-BMI, TSH, and lipid levels in the first trimester could be beneficial for monitoring patients and implementing interventions to reduce adverse pregnancy outcomes.

Association Between Maternal Thyroid Function in Early Pregnancy and Gestational Diabetes: A Prospective Cohort Study.

CONTEXT: Previous studies on the relationship between thyroid gland function and the development of gestational diabetes mellitus (GDM) have reported different results, leading to the need for a cohort study design with a large sample size. OBJECTIVE: We aimed to investigate the relationship between thyroid function in early pregnancy and GDM. METHODS: This was a prospective cohort study based on the China Birth Cohort Study (CBCS), from February 2018 to December 2020. The study took place at a tertiary maternal and child health hospital. A total of 36 256 pregnant women were successfully recruited based on the CBCS. The main outcome measure was GDM. RESULTS: This study consisted of 26 742 pregnant women who met the inclusion criteria, of whom 3985 (14.90%) were diagnosed with GDM, and the women with GDM were older than their healthy counterparts (33.26 ± 4.01 vs 31.51 ± 3.76 years, P < .001). After removing potential influencing variables, we found that increased thyroid-stimulating hormone (TSH) (adjusted odds ratio [aOR] 1.030, 95% CI 1.007, 1.054, P = .012) and subclinical hypothyroidism (aOR 1.211, 95% CI 1.010, 1.451, P = .039), but not free thyroxine or thyroid peroxidase antibody, were associated with the occurrence of GDM. Further analysis indicated a nonlinear relationship between TSH and GDM (P < .05): when TSH ≤ 1.24 mIU/L, the occurrence of GDM was elevated with increasing TSH, but when TSH > 1.24 mIU/L, this trend was not obvious. CONCLUSION: High TSH might be associated with increased risk of GDM.

Levothyroxine Treatment in Pregnant Women with Thyrotropin Levels Ranging Between 2.5 and 10 mIU/L: A Propensity Score Matched Analysis.

Objective: To clarify the association between levothyroxine (LT4) treatment and various adverse pregnancy outcomes in pregnant women with thyrotropin (TSH) levels ranging between 2.5 and 10.0 mIU/L in the first trimester, stratified according to thyroid peroxidase antibody (TPOAb) positivity and TSH level. Methods: This retrospective analysis of retrospectively and prospectively collected cohort data included Chinese pregnant women with TSH levels of 2.5-10 mIU/L and normal free thyroxine levels (11.8-18.4 pmol/L) in the first trimester. All participants were followed up until the completion of pregnancy, and information on LT4 treatment, pregnancy complications, and pregnancy outcomes was recorded. A 1:1 nearest-neighbor propensity score matching (PSM) between the LT4-treated and - untreated groups with a caliper distance of 0.02 was performed using a multivariable logistic regression model. Multivariable-adjusted modified Poisson regression was used to estimate the relative risk (RR) and 95% confidence interval (CI) of LT4 treatment for adverse pregnancy outcomes. Subgroup analyses were also performed in four subgroups simultaneously stratified by TPOAb status (negative or positive) and TSH levels (2.5-4.0 mIU/L as high-normal group and 4.0-10.0 mIU/L as SCH group). The study was registered in the Chinese Clinical Trial Registry (ChiCTR2100047394). Results: Among the 4,370 pregnant women in the study, 1,342 received LT4 treatment and 3,028 did not. The 1:1 PSM yielded 668 pairs of individuals and revealed that LT4 treatment was significantly associated with a decreased risk of pregnancy loss (RR = 0.528, 95% CI: 0.344-0.812) and an increased risk of small-for-gestational-age infants (RR = 1.595, 95% CI: 1.023-2.485). Subgroup analyses suggested that the above effects of LT4 treatment were mainly from TPOAb-negative participants. LT4 treatment was associated with an increased risk of preterm birth (RR = 2.214, 95% CI: 1.016-4.825) in TPOAb-positive pregnant women with high-normal TSH levels. Conclusion: LT4 treatment was significantly associated with a lower risk of pregnancy loss and a higher risk of small-for-gestational-age infants in pregnant women with TSH levels of 2.5-10 mIU/L. An increased risk of preterm birth was observed in the LT4-treated group among TPOAb-positive participants with TSH levels of 2.5-4.0 mIU/L.

Regulation of Gut Microbiota through Breast Milk Feeding Benefits Language and Cognitive Development of Preterm Toddlers.

Feeding practice is essential to growth and development of preterm toddlers. However, the relationship of feeding mode with gut microbiota and neurodevelopment outcomes of preterm toddlers has not been characterized fully. We conducted this cohort study to assess neurodevelopment outcomes and gut microbiota community structures of preterm toddlers who received either breast milk, formula or mixed feeding. Fifty-five preterm toddlers born <37 weeks and 24 term toddlers were recruited in the study. Bayley III mental and physical index scores were measured among preterm toddlers at 12 ± 2 and 18 ± 2 months corrected age (CA). Gut microbiome composition was analyzed by 16S rRNA gene sequencing in fecal samples collected from all participants at 12 months, 16 months and 20 months after birth. We found exclusive breast milk feeding for over three months in the first six months after birth was associated with significant increase in language composite score at 12 months CA (86 (79,97) vs. 77 (71.75,79), p = 0.008) and both language (106.05 ± 14.68 vs. 90.58 ± 12.25, p = 0.000) and cognitive composite score at 18 months CA (107.17 ± 10.85 vs. 99.00 ± 9.24, p = 0.007). The alpha diversity, beta diversity and composition of gut microbiota from those breastfed preterm toddlers not only resembled healthy term toddlers but also followed similar structure of preterm toddlers with enhanced language and cognitive performance. Our results suggest exclusive breast milk feeding for over three months in preterm toddlers leads to optimal cognitive and language development and well-balanced microbiota.